These things have been around since time immemorial, usually variations on a 555 with the trigger pin held low by damp earth, when the earth dries out it starts oscillating. Clever idea to use capacitive sensing so you don't get electrolysis though. With a uC you can do all sorts of clever stuff like check for overwatering as well. Re Battery life, being as this is a long-term monitor, you could shut the uC down and just check the dampness every 15 minutes or even every hour, and then only if there is light on it.You could probably monitor for frost as well (Geraniums don't like that...)

So kudos to the designers for coming up with a clever new take on an old idea.

My husband and I were having a miserable experience this year with geraniums in our windowboxes, something that had always been reliably easy for us. We were wondering, "Is it too hot? Are they not blooming because we just bought weakling plants?" We were away for a couple of days and when we came back the geraniums were in beginning to bud. Apparently, my husband had been overwatering them. Seems that this device could be programmed to also check for waterlogged soil.

I think you've got something there, Janine. A chirp or an electric shock when reaching for cake. It's beginning to sound like that Star Trek episode...you know, the one where they're wearing those collars, and ....

Not sure how I feel abou this. On the one hand, I think it is really cool and it would help me prevent killing houseplants (I'm quite good at it). On the other hand, that chirping seems really annoying. Although, i guess if I JUST watered the plants.... OK, so this is good for behavior modification. Maybe i can also get something that shrieks when I cut a piece of cake...Or maybe my treadmill can holler out in pain when I haven't used it in days....